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Renewable Energy 66 (2014) 381e390

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Renewable Energy

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Cassava as an energy crop: A case study of the potential for anexpansion of cassava cultivation for bioethanol production inSouthern Mali

Søren Bech Pilgaard Kristensen a,*, Torben Birch-Thomsen a, Kjeld Rasmussen a,Laura Vang Rasmussen a, Oumar Traoré b

aDepartment of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, DenmarkbMali Folkecenter, Faladié, SEMA, Rue 800, Porte 1293, Bamako, Mali

a r t i c l e i n f o

Article history:Received 22 August 2012Accepted 20 December 2013Available online 21 January 2014

Keywords:BioethanolCassavaMaliProduction system

* Corresponding author. Tel.: þ45 256 788351 859, þ22501.

E-mail address: sk@geo.ku.dk (S.B.P. Kristensen).

0960-1481/$ e see front matter � 2014 Elsevier Ltd.http://dx.doi.org/10.1016/j.renene.2013.12.021

a b s t r a c t

Cassava based bioethanol production is a promising alternative to conventional fossil fuels and com-mercial production is already well established in several countries. A production based on small holderproduction may involve a transformation of the existing production system and it is therefore imperativeto investigate opportunities and barriers for expansion of cassava production. This paper investigates thepotential for an expansion of cassava cultivation for bioethanol production in Southern Mali. It is basedon a questionnaire survey with 65 households in 2 villages in Loulouni municipality, which representtwo major agro-ecological environments in the Soudan-zone in Mali. The results reveal that farmers areexperienced cassava producers and are interested in an expansion of cassava cultivation for bioethanolproduction and that suitable areas are available, especially for an expansion of the Attieké cassava variety.Little competition with food crops is likely, as cassava most likely would replace cotton as primary cashcrop, following the decline of cotton production since 2005 and hence food security concerns appear notto be an issue. Stated price levels to motivate an expansion of cassava production are close to acceptablelevels to make bioethanol production profitable and the advantages of a continuous demand at agreedprices may motivate farmers to accept prices which would make bioethanol production competitive.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction

Within the past decades, there has been an increased interest inthe potential of bioethanol as a substitute to conventional fossilfuels e but equally a number of concerns have been raisedregarding the possible negative impacts. One of the early argu-ments for the substitution was the ability of biofuels to mitigateclimate change through a reduction in the emissions of greenhousegasses (GHG). However, it is still discussedwhether first-generationbiofuels actually leads to a reduction of GHG emission [1e4]. Theinterest for bioethanol production has been driven by both a‘Northern’ as well as a ‘Southern’ agenda [5]. The Northern agendarefers to concerns regarding fuel security, high oil prices andclimate change while the Southern agenda focuses on the potentialof biofuel production to promote economic development andcreate employment in rural areas as well as reducing imports of

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fossil fuels [6e8]. Recent discussions related to GHG reductionpotential have focused on the land use change aspect. It has beenstated that clearing of forest land for production of biofuel feed-stock can incur large carbon losses e referred to as ‘carbon debt’[2,9]. Therefore, some argue that, in order to capitalize the reduc-tion potential, cultivation of biofuel feedstock should be con-strained to areas with low carbon content [4], e.g. depleted or wastelands, fallowed land, or land presently under cultivation. Recentresearch has shown that the size of the carbon debt might beoverestimated as useful trees are left untouched in many agricul-tural systems, e.g., in Southern Mali [10].

In terms of the economy of biofuels, Rosegrant et al. [6] statesthat price levels of crude oil well above $60e70 per barrel willenable biofuels to become competitive with fossil fuels. Priceswithin the past ten years have for most of the period been abovethis level. However, price fluctuations have been significant, vary-ing from a maximum of $121 per barrel in the second quarter of2008 to a minimum of $44 in the first quarter of 2009 [11], yet mostof the time above $75. An important addition to the fluctuations inoil prices is the fact that prices on major agricultural commodities

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390382

are increasingly correlated to oil prices (so when competitivecompared to petroleum, it also has to compete with high prices onfood crops e e.g. cassava in this study).This discussion leads to oneof the main concerns related to increased biofuel production e thecompetition between production of biofuel and food production[5,12e17]. The concerns are directed towards a potential competi-tion for land and other resources between food and fuel production.If biofuel production out-competes the production of food crops, itmay lead to reduced food availability and decreased food securitye

a threat to poor, and particularly urban, communities in developingcountries. However, it has been argued that crops cultivated forbiofuels are no different from other commercial crops, at least fromthe farmer’s perspective [18]. Although not always the case,development of cash crop production may lead to improved foodsecurity. A review of small holder cotton production in Mali be-tween 1960 and 2003 found an increase of 70% in cereal productionper capita compared to non-cotton farmers [19]. Furthermore, arecent study from Cambodia of the expansion of cassava cultivationas a biofuel feedstock showed no competition over land betweenthe new cash-crop cultivated on upland fields, and the traditionalstable food, rice, cultivated in low-land flood-irrigated fields [20].This highlights the importance of local specific studies with regardsto, among other factors, local farming traditions and landscapeconditions when evaluating the impact of biofuel production onfood security.

Cassava (Manihot esculenta Crantz) is increasingly attractive asan energy crop due to its high rate of CO2 fixation, high water-useefficiency, high carbohydrate content, and superior starch conver-sion ratio for ethanol compared to other crops [21]. The plantthrives and yields well under conditions of low rainfall and inacidic, marginal soils, and has the potential for continuous har-vesting. All these characteristics make it a commonly grown low-cost crop, well suited for small-scale biofuel feedstock production[11]. Cassava has been used for bioethanol production in Brazil andAsia for several years [21] and several studies have investigated thepotential in sub-Saharan Africa [22].

As cassava is already widely cultivated in parts of Mali, it ispertinent to analyze the potential for increased cassava productionfor bioethanol production. Therefore, the overall objective of thepaper is to investigate the potential for an expansion of productionfor bioethanol production. This will be done by addressing thefollowing five questions:

� What is the present situation of cassava production in a studyarea in Southern Mali?

� What are the potentials and barriers for increased cassava pro-duction for bioethanol production? In particular, is land avail-ability a constraint?

� On which areas and which farmers are likely to expand cassavaproduction?

� Will an expansion of cassava production have negative effectson food security?

� What economic conditions would facilitate an increasedproduction?

2. Materials and methods

The research reported in this paper is based on fieldwork carriedout in Loulouni municipality, Kadiolo District, Sikasso Region inSouthern Mali in February 2010 (see Fig. 1). The area enabled us tostudy the potential for expansion of cassava production in differentphysical environments. The fieldwork included a questionnairesurvey with farmers in 2 different agro-ecological zones supple-mented by interviews with key informants (farmers, farmers

associations, local authorities). 65 respondents were selected forthe questionnaire survey using a systematic stratified samplingscheme. The questionnaire survey investigated issues on farmingsystem and opportunities for cassava expansion and was part of alarger study on the potential for cassava-based bioethanol pro-duction in Southern Mali [10,23]. In addition, a Worldview-2multispectral high resolution satellite image with approx. 2 mspatial resolution from January 2010 supplemented by 1999Landsat TM images with 15 m resolution, were used to map landuse, supported by field observations.

It was intended to gain an impression of wealth distribution inthe study areas, as an indicator of the level of assets and meansavailable in individual households. This is hypothesized to be linkedwith farmer’s willingness and attitude towards changes in thecurrent production system. Thus, it is assumed that farmers whoare relatively well-off are already engaged in cash crop production(as this is generally the main source of income in the area) andtherefore interested in further income generation. As accurate in-come figures are difficult to establish, a proxy was used whichdescribes the relative wealth of households based on a compositeindicator: housing standard, ownership of means of transport. Bothtypes of assets contain a range of options which require less ormore capital investment (e.g. oxcart and a car being examples of theextremes for means of transport) and thus indicators of the level ofhousehold or respondent wealth status. Households commonlyowned several assets at different wealth levels (e.g. both an oxcartand a bicycle), and the interpretation focuses on the most valuablemeans of transport and ignores the less costly to make itmanageable.

A two-step cluster analysis was performed to identify groups offarmers with similar wealth indicators. Three clusters wereretained, as information on the quality of the classification showedthis number of clusters to yield meaningful information.

2.1. Study area and data

Cassava has been one of the main food staples in this area ofsouthern Mali for decades [23]. National yields are estimated to be15e20 T/ha [24]. It is an important tuber crop, which has manydifferent uses. One of the main advantages of the crop is the abilityfor in situ storage in the field, allowing fresh tubers to be harvestedduring periods of the year where demand is high. Most productiontakes place in the Sudan Zone of Mali (900e1100 mm/year), yetcassava is exported to other regions in the country [23].

The study area is a complex landscape with large differences insoil type, topography and humidity conditions. Fig. 2 presents themain landscape units in the case area. The classification was doneon the basis of the QuickBird image. The following four landscapeunits have been identified:

A) Flat alluvial plainMost dryland crop production occurs in a flat plain situated in

between the elevated areas and the low-lying seasonally floodedareas e this unit is by far the largest within the study area (seeTable 1). Many fields are cultivated in a shifting cultivation orrotational system, where fields are left fallow for a number of yearsafter being cultivated in a crop rotation of cereals and cash crops(previously cotton).

B) Lateritic plainElevated areas, only marginally suited for arable production.

These areas are mostly covered with shrubs and forests and areused for firewood collection and as grazing areas. There is limitedcultivation within this second largest landscape unit, yet fields

Fig. 1. Study area and sample villages.

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390 383

patterns indicate that is has previously been cultivated moreintensively, e.g. with cotton.

C) Escarpment and plateauThis area resembles inselbergs, with steep slopes and rocky

surfaces. The area is largely unsuitable for crop production.

D) Seasonally flooded area (bas-fond)The last landscape unit represented in the study core area is a

low-lying seasonally flooded zone, of which most is intensivelycultivated. The abundance of water allows the cultivation of severalcrops per year. It is cultivated with crops which respond well toabundant soil moisture, such as rice, cassava and sweet potatoes ethe two latter, however, typically on mounded ridges in order tokeep the tubers from getting waterlogged.

The areas covered by these landscape units, within the areashown in Fig. 2, are given in Table 1.

2.2. The study villages

In order to investigate how farmers respond to cassava pro-duction under different environmental settings, two differentareas, including three villages, representing slightly different bio-physical settings were chosen as the location for detailed surveys:

1) Two villages, Sièouba and Facokourou Courani, were selected torepresent areas with an existing high production of cassava, inthe wet-lands as well as in the alluvial plains. The two villagesare located north-east and south-west of the large wetland(alluvial plain; bas-fond) respectively (see Fig. 2 and site I inFig. 3).

2) The village of Perasso was selected to represent areas withlimited current cassava production and limited access to wet-land areas. It is representative of the southern part of LoulouniCommune and the area further south (towards the border to

Fig. 2. Landscape units in study area.

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390384

Ivory Coast). Small areas are cultivated with cassava, mainly insmall/narrow wetlands in the proximity of the river (see Fig. 2and site II in Fig. 3).

3. Theory

Introduction of a new component or new crop into existingproduction systems represents an innovation or systems change

Table 1Areas of landscape units within the study area delimited in Fig. 2.

Land class map Square kilometres Percent of totalarea (%)

Flat alluvial plain 46.0 53Lateritic plain/interfluves 22.9 26Escarpment/plateau 8.1 9Seasonal flooded area (bas-fond) 10.3 12Total area 87.3 100

which may be desirable and possible to some farmers whileothers may be reluctant or unable to undertake it [25]. The abilityof a farmer to adopt a new component into present farmingpractises depends on a number of factors. From a livelihoodperspective, these would often be categorized as human, socialand physical capital. Differences in capital endowment have beenfound in many studies to be important determinants of farmers’‘room for manoeuvre’ [26]. In case of production of cassavafeedstock for biofuel, FAO [18] argues that the scale-neutraltechnology is favouring an equal distribution of the benefits.However, German et al. [27] report of evidence from countrieswith already established biofuel industries, suggesting that thewealthier stakeholders/producers are better able to capture thebenefits of the emerging biofuel industry. Some of the importantfactors or capitals affecting peoples or households ability torespond to new options, livelihood activities, are among othersthe availability and access to land and labour availability [28].These themes therefore constitute core elements in the ques-tionnaire survey.

Fig. 3. Land use in the two sub-areas, shown in Fig. 2.

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390 385

4. Results

4.1. Land use history

Cotton used to be cultivated extensively on the sandy and e to alesser extent e gravelly soils, and substantial areas of fallow landcan be found where cotton used to be grown. Many of these fallowplots have an age of 5e10 years, as cotton production has declinedover this period.

Sieouba and Facokourou CouraniOver the last decades cultivation has expanded into the large

wetland area between Sieouba and Facokourou Courani. The cropsgrown in the wettest parts have mainly been rice and e to anincreasing extent e cassava (see site I in Fig. 3). A lowering of thewater table has been observed, allowing cultivation to expand intopreviously flooded areas. However the largest individual land useclass is ‘fallow land’.

PerassoThe dominant land use class in Perasso is secondary forest and

bushland representing more than one fifth of the area in site II(Fig. 3). Cassava is mainly grown on the lower parts of the alluvialplain towards the seasonal flooded areas which are dominated byrice cultivation. The proportion of cultivated upland fields aresimilar to site I, but with far less land under fallow.

4.2. Production system

The arable production consists of a mix of cash crops and sub-sistence crop production. Previously cotton production (with sale toCompagnie Malienne pour le Développement des Fibres Textiles(CMDT)) was themain dryland cash crop, but this has virtually beenabandoned since 2005 due to falling profitability. Farmers withaccess to bas-fond areas cultivate rice, yams and sweet potato be-sides cassava as main cash crops, while farmers with fields locatedon dryland cultivate peanuts and maize as cash crops. Subsistencecrops include millet, sorghum and maize as well as a variety oflegumes and pumpkins. Agroforestry practises are normal,whereby useful trees are left in the fields to provide shade anddifferent products. Common trees are Karité, Néré, Cashew andMango trees.

On several production indicators, Sièouba and FacokourouCourani villages show sign of more intensive production thanPerasso (see Table 2). Thus, average farm size is 31% larger inSièouba and Facokourou Courani villages (17.7 ha vs. 13.3 ha inPerasso) and the proportion of the land which is currently culti-vated is also higher (65% vs. 50% in Perasso). Furthermore, theproportion of long term fallow land is much smaller (8% vs. 30% inPerasso).

A significant proportion of farmers in both subareas use inor-ganic and organic fertilizers. A common dosage is 100 kg ofammonium (N) and 50 kg of ‘super complex’ (P) fertilizer/ha, at a

Table 3Cassava production in case area.

Sièouba andFacokourouCourani

Perasso

% of respondents cultivating cassava 100 83Average cassava area (ha) 4.8 1.2History of cassava cultivations

(years of cultivation)18 5

Use of inorganic fertilizer on cassava(% of cassava farmers)

100 70

Use more time on cassava than othercrops (% of households)

69 68

Use hired labour (% of households) 91 78Cassava yield (T/ha) 11 8.2 (6)a Attieké

6.9 (21) Bonouma6.2 (6) othervariety

Rank of cassava as 1st. source ofhousehold income

73% 5%

Average maximum sellingprice (FCFA/kg)1

73 66 (6) Attieké100 (21) Bonouma120 (6) Othervariety

Average minimum sellingprice (FCFA/kg)1

41 38 (6) Attieké53 (21) Bonouma60 (6) Othervariety

a Number in brackets indicate number of farmers cultivating the particular cas-sava variety.

Table 2Farm size, cultivated area and fallow land.

Sièouba and FacokourouCourani (n ¼ 35)

Perasso(n ¼ 30)

Average farm size (ha) 17.7 13.3Average cultivated area (ha) 11.5 6.7Average short fallow (<20 years) (ha) 4.5 3.3Average long fallow (>20 years) (ha) 1.5 3.3

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390386

price of 30e40.000 FCFA/ha. Short term (<20 years) and long termfallow (>20 years) is also used to allow soil nutrient content toregenerate after a period of cultivation.

Land ownership is a complex mix of individual and communal/clan ownership. The complexity mirrors the household composi-tion, where nuclear families are united in extended households andhave differentiated access to land and labour and other importantresources according to their age and social ranking in the com-munity. The vast majority of cassava farmers in the two sub-areashave exclusive user rights to the land where cassava productiontakes place, which means that they can decide on land manage-ment issues without interference from others (70% in Sièouba andFacokourou Courani villages vs. 92% in Perasso).

4.3. Cassava production in study area

A number of varieties of cassava are cultivated in the study area.The two dominant varieties are:

Bonouma (12 month crop cycle) is almost exclusively producedin wetlands (bas-fond), which are intensively cultivated with manytypes of crops (sweet potatoes, rice, yams). Bonouma is thereforethe dominant variety in villages with access to large wetland areas,where it covers 70e90% of the cassava area. It is a sweet cassavawhich can be consumed after limited preparation (e.g. boiled), butis labour demanding in planting due to the preparation of the largemounded ridges.

Attieké is short cycle variety (6e9 months) which can be culti-vated on dryland soil. This makes it a flexible crop which is adaptedto different environments. In villages with limited access to bas-fonds, it may cover 80e90% of the cassava area. It is known as abitter variety and needs several steps of processing before it can beconsumed, to reduce the content of cyanide glucosides. Labourinput is often less, compared to Bonouma, as it can be grown insmall ridges on upland fields.

In addition, the varieties Abidjanka and Agassiwere cultivated insmaller amounts (<5% of production).

The Attieké variety has been cultivated for approximately 10years in the region. It was originally introduced by immigrants fromIvory Coast, where it has a long cultivation history. The Bonouma isprimarily sold on demand to buyers from all regions of Maliwhereas the Attieké variety is sold in local markets and in Sikasso,which is the regional centre. Farmers leave the crop in the soil, asstorage, until an order has been placed, or until a monetary needarises which requires the sale of crops.

Important differences were found between the two subareas. InSièouba and Facokourou Courani villages, all respondents cultivatecassava and apply inorganic fertilizer. The cassava areas are quitelarge (average: 4.8 ha) and the crop has a long history of cultivation(average: 18 years) (see Table 3). In contrast, 17% of the respondentsin Perasso do not cultivate cassava, and only 70% of the cassavafarmers use inorganic fertilizer. The average cassava area is rela-tively small (1.2 ha) and the cultivation is quite recent (5 years onaverage). In addition, 27% of the cassava farmers cultivate Attieké inaddition to Bonouma, which is estimated to be a much higherpercentage than in Sièouba and Facokourou Courani villages.

4.4. Crop calendar

Planting generally takes place from July to September and theactual planting dates depends on the availability of land: the oldcrops need to be harvested before the new crops can be planted andlabour availability (especially when work teams “entre-aide” areengaged). The Bonouma variety is planted in mounded ridgeswhere tuber development is easy, facilitated by moisture stored inthe ridges and loose soil. After a few months weeding takes placeand fertilizer is supplied to the individual plants and the ridge is re-created. Some farmers indicated that planting depends on soilhumidity andmay continue later than September. However, certainmoisture content is required for the 1st weeding, which needs to betaken into account by the farmer when deciding on the plantingperiod. A mounded ridge with a length of approximately 2 m.(variations from 1 to 6mwere observed) and a height of 50 cmmayproduce 25 kg of tubers. Harvest dates generally depend on varietycrop cycles. Thus, Attieké varieties may be harvested any time afterFebruary when they reach maturity while Bonouma is ready forharvest in May. However, the main production coincides with thebeginning of the rainy season (MayeJune) to September, when thesoil is sufficiently moist. In the case of Attieké, planting is done insmaller ridges on the lighter soils and harvest can take placethroughout the year after maturity. Farmers indicate that after theonset of rains, tubers increase in weight as the plant benefits fromearly rains, even after maturity.

4.5. Labour inputs

Cassava is cultivated with a combination of family labour,mutual aid (“entraide”) and hired labour. Hired labour was used by91% of the farmers in Sièouba and Facokourou Courani villages andthe similar figure was 78% in Perasso (see Table 3). The hired labourmay be the village group (a “Ton”) or other groups which are hiredeither on a temporary basis (daily or weekly) or for a fixed agree-ment (e.g. field preparation). Most cassava field works coincidewith those of other crops (planting during period of sufficient

Table 4Wealth indicators.

Indicator Cluster 1(Rich)

2(Middle)

3(Poor)

No. ofHH.

Transport Expensive (Caror motorbike)

32 0 0 32

Medium (Moped) 0 13 0 13Basic (Bicycle,oxcart)

0 0 19 19

Housing (roofingmaterial)

Expensive (sheetmetal)

17 8 8 33

Basic (thatch) 15 5 11 31Descriptive

characteristicsand location

Workforce inhousehold

11 6 6 n/a

Farm area 20 13 11 n/aPerasso 2 13 14 29Sieouba and 30 0 5 35

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390 387

rainfall). This may lead to competition for labour, which can be aparticular problem for households with limited labour availability.Cassava is a time consuming crop due to the labour intensiveplanting (especially to build the mounded ridges for Bonoumacultivation) and harvest operations and 68% of the farmers in bothsub-areas report that they use more time on cassava productionthan on other crops. In the case of mutual aid, the labour is unpaid,but the person benefiting from the assistance must pay for food (avalue of 30.000 FCFAwas indicated in one focus group interview). Itis only available to persons who are able to contribute withmanpower themselves. Thus, old or sick persons have no access tothis form of assistance. In some villages (e.g. Facokourou Courani)cassava farmers are organized in cooperative which regulatesmarketing and organizes members in work teams for mutual aidfieldwork.

FacokourouCourani

Total 32 13 19 64

4.6. Cassava economy and yields

Average yield levels vary considerably between the two sub-areas. The fertile bas-fond provides average yields of 11 T/h to thefarmers in Sièouba and Facokourou Courani villages, while yieldsare 30% less in Perasso (Table 3). Both yield levels are significantlylower than the national averages of15e20 T/ha, according to FAOstatistics (21). Both Bonouma and Attieké varieties are cultivated ascash crops and are marketed locally as well as purchased byregional and national traders (in particular Bonouma). Cassava wasmentioned as the most important cash crop by 73% in Sièouba andFacokourou Courani villages, whereas this was only true for 5% ofthe cassava farmers in Perasso. Maize and cotton were moreimportant cash crops in this village.

The price level of cassava varies considerably during the yearand between varieties. Cassava serves as a “hunger gap” closerduring the onset of the rainy season around June in the mainmarkets (Segou, Mopti), before other subsistence crops are readyfor harvest. This period therefore coincides with the highest pricelevels recorded. Price information from Perasso reveals thatmaximum prices for Bonouma are considerably higher than forAttieké (100 FCFA/kg vs. 66 FCFA/kg). During the remainder of theyear, prices decrease to 20e70 FCFA/kg (average: 50 FCFA/kg) forBonouma and 15e100 FCFA/kg (average:38 FCFA/kg) for Attieké.Due to its capacity to be stored in the soil, it is an attractive cashcrop, as farmers can wait until prices are high enough before har-vesting. However, it happens that fields are not harvested becausethere is no demand.

4.7. Wealth

A cluster analysis of the wealth status of households usingownership of means of transport and housing standards as in-dicators resulted in three quite distinct groups. Table 4 outlines themain wealth characteristics of the three groups. Descriptive char-acteristics of the three groups (labour availability, farm size andlocation) are also included in the table, to illustrate the differencesbetween the groups. For all groups, the wealth status is mostevident concerning ownership of means of transport while differ-ences in terms of housing standard are less clear.

Rich (Cluster 1): This group is clearly the most well-endowedconcerning means of transport (all owners of car and motorbike)and has a slight majority of owners of houses with sheet metalroofing (including 100% of households with houses exclusively builtin brick walls and with sheet metal roofing). In addition, the 32households in this group (50% of all) both have the largest work-force and cultivated area at their disposal. Almost all of thesehouseholds (94%) live in Sieouba and Facokourou Courani.

Middle (Cluster 2): This is an intermediate group in terms ofwealth. All of the households owning a moped are found in thisgroup. More than half of the households in this group live in housesof superior housing quality (sheet metal roofing). In terms ofcultivated area this group is intermediate between cluster 1 and 3whereas the workforce availability is equal to that of pooresthouseholds. All these households live in Perasso.

Poor (cluster 3): This group is composed of the least advantagedhouseholds. All households owning a bicycle or oxcart as the mostexpensive means of transport are found in this group. In terms ofhousing quality the group is also disadvantaged as 58% of thehouseholds live in houses with thatch roofs (among these are 100%of the households with the most basic housing quality (clay walland thatch roofing). These households are the least endowed interms of farm area while workforce availability is equal to that ofthe medium wealth group. Cluster membership is dominated byhouseholds from Perasso, which constitute 74% of this group.

In summary, it appears that three clusters can be identifiedwhich divides the population into different wealth groups. Eachgroup has different opportunities for agricultural production, as theagricultural workforce and cultivated area varies substantially.There is a clear geographical variation in wealth distribution, as therichest cluster is dominated by households from Sieouba andFacokourou Courani. In contrast, a vast majority of households inthe intermediate and poor wealth groups live in Perasso. For thelatter two groups, the importance of cassava production, expressedas the relative share of cassava area, was much smaller than incluster 1 (24% and 17% for cluster 2 and 3 respectively versus 43%for cluster 1). This finding correlates with the fact that cassava is themain source of income for most households in Sieouba and Faco-kourou Courani and only for a small minority in Perasso (Table 3).

4.8. Interest in expansion of cassava cultivation

The results presented above indicate that cassava is already apopular crop and has an important place in household economiesin the study area. In most cases, it is part of a cropping systemwhich includes a mix of subsistence and cash cops and any changehas impacts on food supply and household revenue. The fact thatthe farmers already have experience with cash crop production(formerly cotton) and that this production now has virtually ceasedrepresents an important premise for this paper. We are thereforeinterested in investigating which areas the farmers prefer in case ofexpansion of cassava production and the environmental impact of ahypothetical expansion of the cassava area (measured in terms of

S.B.P. Kristensen et al. / Renewable Energy 66 (2014) 381e390388

trees to retain in case of new land being cultivated). We are alsointerested in the dynamics of a potential expansion of the cassavaarea (measured in terms of threshold selling price quoted byfarmers to motivate expansion of the cassava area). This informa-tion was collected by asking farmers directly about the thresholdselling price, an approach which implies a certain degree of un-certainty (farmers may base their answer on opportunistic motivesrather than exact information about realistic price levels).

In both subareas, a vast majority of cassava farmers expressed aninterest in expansion of their cassava production (see Table 5).However, farmers believed that an expansion should be motivatedby an increase in sales prices. Farmers in Sièouba and FacokourouCourani villages on average expected a sales price which was 30%higher than the current maximum price (95 FCFA/kg vs. 73 FCFA/kg), while farmers in Perasso desired a 100% price increase(210 FCFA/kg vs.100 FCFA/kg). The desired prices listed in Table 5are hypothetical and farmers may not necessarily be aware ofrealistic price levels. In particular, a potential demand for cassavafor bioethanol production would be more evenly distributed overthe year and farmers might be motivated to accept lower prices inreturn for guaranteed and stable prices over the entire year. Thesefactors should be taken into consideration when interpreting theresults. In both subareas, the preferred location for an expansionwas former forest areas (58% vs. 66%). In Sièouba, the forest sitepreference was quite low (only 37%), reflecting the limited avail-ability of forest areas (only found among 6% of farmers vs. 53% inFacokourou Courani). All farmers except one indicated that theywould leave useful trees in newly cultivated areas, such as Karite,Nere and mango trees, to provide shade and forest products.

The main incentive mentioned by farmers in Sièouba andFacokourou Courani villages to increase production was theperspective of increased income. The main obstacle mentioned wasa lack of labour or land. Unfortunately, similar information was notcollected in a systematic manner in Perasso. The few answersretrieved indicate similar reasons for not wanting to expand cas-sava area as those given in Sièouba and Facokourou Couranivillages.

5. Discussion

The use of cassava for biofuel production has proven to becompetitive in several parts of the world [29,18]. This study hasinvestigated the potential for expansion of cassava production forbiofuel production in a case area in Mali, to assess the feasibility of

Table 5Potential for expansion of cassava production.

S. and F-C.(n ¼ 35)

Perasso (n ¼ 30)

Interest in expansion of Cassava(% of respondents)

91 87

Minimum price to make extensionof cassava interesting (FCFA/kg)

95 210

Forest the preferred location forcassava expansion (%)

58 66

Will leave useful trees in newcassava field (%)

100 97

Main reason for wanting to expandcassava area (% of households):

1) increase income, 2) there is ademand,

1) 862) 3

Very few answers inquestionnaires

Main reason for not wanting toexpand cassava area (% ofhouseholds): 1) insufficientlabour availability, 2) insufficientland availability

1) 62) 3

Very few answers inquestionnaires

bioethanol production in this country. The study concentrated onthe potential and barriers for expansion of cassava production fromthe perspective of the current farming system. The study was car-ried out in two different villages located in different biophysicalenvironments, to investigate the impact of expansion of cassavaproduction in diverse settings. This discussion centres on the po-tential and barriers for expansion of cassava production in light ofthe availability of production factors needed for agricultural pro-duction (land, labour and capital). In addition, it discusses the po-tential economic and food security impact of an expansion ofcassava production.

5.1. Potentials

Cassava cultivation has a long history in Loulouni municipality,where two main varieties are cultivated extensively (Bonouma andAttieké), while a number of other varieties are less important.While Attieké can be cultivated in both upland and lowland con-ditions, Bonouma is mostly cultivated in fertile lowland areas withabundant moisture availability. The more favourable biophysicalconditions in Sièouba and Facokourou Courani villages reflects thispattern, as cassava production is more prevalent with a greateremphasis on Bonouma than in Perasso. In addition, cassava pro-duction is not as old in Perasso as in Sièouba and FacokourouCourani villages. Examining the current land use pattern and landavailability in the two case areas, it appears that Bonouma culti-vation is already occurring to the extent possible and furtherexpansion thus seems difficult, while an expansion of Attiekécultivation is quite likely, as upland soil is available, either in theform of current fallow areas in the lateritic plain or replacing othercash crops in the production system, e.g. cotton on the flat alluvialplain, which has experienced a drastic decline in cultivated area inrecent years.

Land is thus available in general for expansion of cassava pro-duction and the results indicate that most farmers are familiar withcassava productionwhere it already plays an important role as cashcrop. Indeed, for a majority of farmers in Sièouba and FacokourouCourani villages, it is currently the most important cash crop.Whilethis is the case for a small minority in Perasso, the availability ofland for future expansion may change this situation. Almost allfarmers responded that they were interested in the expansion ofcassava production and only a few mentioned that lack of land orlabour may be an obstacle for expansion of cassava production.

The farmers in Sièouba and Facokourou Courani villages pres-ently seem more able to expand the cassava production. They aregenerally richer and have more labour and land at their disposalthan households in Perasso and also appear to have more experi-ence with production and sale of cassava. This result confirms thefindings of Rasmussen et al. [23]. However, an increase in cassavaproduction for bioethanol using primarily Attieké would allowfarmers in Perasso to increase production relatively easy, as thereare large upland areas available.

A lot of research has focused on the negative impact biofuelproduction may have on food security, if food crops are used forbiofuel production thereby reducing food availability [12,14,15].This dilemma does not seem to be an issue in the present case, as anexpansion of the production of Attieké for bio-ethanol is unlikely tohave negative overall impacts on food security, neither locally nornationally: Firstly, the relatively low prices which may be obtainedimply that the Bonouma production, of considerable relevance tofood security in the Segou andMopti regions, will not be affected. Itwill still be economically rational for farmers to give priority to thisproduction. Secondly, the current, rather limited, Attieké produc-tion for consumption, mainly in Sikasso, is not likely to be nega-tively affected either, since it is sold at similar or slightly higher

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prices than those expected for bio-ethanol purposes. Thus, themain effects on food security of increased demand for Attieké areexpected to be indirect in the forms of (1) that a higher total de-mand for agricultural products may lead to higher prices, asobserved at the global scale, increasing incomes (and thus foodsecurity) of the rural population, yet cause problems for the urbanpopulation, and (2) that in case of drought, food shortage may beavoided by diverting cassava production from bio-ethanol to fooduses.

5.2. Barriers

The most significant barrier for the expansion of cassava culti-vation in the case areas appears to be the price demanded byfarmers. Indeed, farmers on average quoted an increase in salesprice ranging from 30 to 100% compared with current sales prices.Such price levels would be prohibitive for feasible biofuel produc-tion in Mali [23]. However, several factors suggest that the desiredprice level might be exaggerated. Firstly, farmers may have unre-alistic expectations to high price level because they were unawareof the pricemechanisms in the biofuel sector. In other words, if theyhad been better informed of the market conditions to make biofuelproduction profitable, their answers might have been more real-istic. In addition, if a guaranteed price mechanism could be put inplace, farmers are expected to agree to lesser prices therebyfollowing market dynamics seen in other sectors. The market forcassava for bioethanol production would most likely have a moreevenly distributed demand over the year. This should be attractiveto farmers who are often faced with cash shortage over a consid-erable part of the year, and could be an additional incentive forthem to accept more modest price level for increase production.

Households in Perasso are currently little involved in commer-cial cassava production and have less assets, in terms of farm areaand labour to invest to increase cassava production. However, theland use analysis reveals that forest land is more abundant in thisarea than in Sièouba and Facokourou Courani villages (especially inSièouba) and would be available for cassava production if ownerrights permit. In addition, the farmers in Perasso are expected to beeager to increase income through increased cassava production. Incontrast, farmers in Sièouba and Facokourou Courani villages haveless opportunity to expand cassava production, as available forestareas are limited. In addition, the current production of cassava andother cash crops in the fertile bas-fond areas is expected to make anincrease in up-land Attieké production less attractive e depending,however, on the price level of the Attieké.

Current problems faced by farmers cultivating cassava includedcrop damage by livestock. As Attieké is the only green crop onupland fields during the dry season, it may attract livestock lookingfor grazing. Farmers mentioned that fencing may be a solution.Others indicated that livestock owners need to pay attention totheir animals, as divagation is a known problem and is prohibitedby legislation.

6. Conclusion

This paper has investigated the potential for bioethanol pro-duction in Mali based on an expansion of existing small holdercassava production. It focused on the implications for the existingfarming system based on a case study in Southern Mali whichidentified potentials and barriers for increased cassava productionin two different biophysical zones. The case study revealed thatcassava production has a long history in the region and severalvarieties suitable for either lowland or upland conditions arecultivated in the area. Significant differences in the role of cassavain the farming systems were identified, in terms of area cultivated,

crop yields and economic importance according to access todifferent landscape units. In general, cassava production, primarilyusing the bonouma variety was more commercially oriented inareas with access to lowland, seasonally flooded areas (Bas-fond).In contrast, in the drier upland conditions of the alluvial plaincassava production, primarily using the Attieké variety occurred ona smaller scale and was more subsistence oriented.

The potential for expansion of cassava production is promisingin terms of land availability and farmers’ interest. Significant up-land areas are available for enlarged cassava production, includingboth fallow areas and largely uncultivated lateritic plains/in-terfluves. The attractive lowland areas are already intensively usedand it is not likely that more land can be cultivated. Most farmerswere interested in an expansion of cassava production provided itwas economically feasible. The desired sales prices mentioned byfarmers differed widely and were generally higher than currentprices and this may constitute the most serious obstacle for theexpansion of cassava production. However, it is likely that anattractive sales agreement with guaranteed prices and continuousdemand over the year will motivate farmers to a price level thatwould make cassava-based bioethanol production profitable.

It should be noted that the Bonouma and Attieké varietiesshould effectively be considered as two separate crops for allpractical purposes. They are mostly grown on different soils,requiring different techniques and labour inputs, follow differentcultivation calendars, obtain different prices, and have differentuses, distribution channels and significance for Mali’s food security.The results obtained demonstrate clearly that basing bio-ethanolproduction on the Attieké variety is the only realistic option.

Cassava production is the primary source of income for themajority of farmers in the case areas and has contributed positivelyto improved living standard and wealth. It is therefore likely thatexpansion of Attieké production in upland areas would have posi-tive income effects. This is particularly interesting from a devel-opment perspective, as these areas were typically cultivated bypoorer households. The expansion of cassava production couldreplace cotton as a cash crop, after the drastic decline in cottonproduction in the area, and provide an important source of incomewithout negative impacts on local and national food security.

Acknowledgements

The authors would like to thank two anonymous reviewers fortheir comments which helped improve the manuscript. Theresearch project was part of the DANIDA-funded study “Faisabilitédes resources de l’energie renouvelable au Mali” (see http://www.frsemali.org/for more information).

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